Process Control Management:
A process is an executing program. It is considered the standard unit of work within a computer system. Every executing program is treated as a process. This includes not only application programs, but the programs within the operating system itself. The process concept considers the program, together with the resources that are assigned to it, including memory, I/O devices, time for execution, and the like. When admitted to the system, each program is assigned memory space and the various resources that it initially requires to complete its work. As the process executes, it may require additional resources, or it may release resources that it no longer needs.
The operating system performs various functions with processes, including scheduling and memory management, by providing the various services. Processes must often be synchronized, so that processes sharing a common resource do not step on each other's toes by altering critical data or denying each other needed resources.
Systems also provide communication capability between different processes. Processes may cooperate with each other by sending messages back and forth using interprocess messaging services.